Almost all laboratories store thermosensitive products such as blood, tissues, cells, bacteria, etc., in ml vials, that fit into an industry standard storage container. The container, in turn, fits into a standard freezer rack, set by industry standards, designed to accommodate the maximum amount of storage containers, while fitting the internal dimensions of the cryogenic storage freezer. Such cryogenic containers are typically in the form of a simple cardboard or plastic box that is suitable for long term storage at ultra-low temperatures.
Further, the number of vials that can be stored within the storage container is standardized within the industry. Examples of some industry standard configurations for the number of vials include: 81 vials (in a 9×9 configuration), 100 vials (in a 10×10 configuration), and 64 vials (in an 8×8 configuration.) Typically, vials are placed in the standard industry storage container, which is placed in the cryogenic freezer, usually a −80 C freezer or a liquid nitrogen (LN2) freezer for freezing and storage.
Much energy is required to maintain the thermosensitive products at cryogenic temperatures. Accordingly, cryogenic storage freezers are compact in design for energy and spatial efficiency. Each cryogenic freezer has a finite amount of space and little tolerance for varying sizes of containers within. Much thought and experimentation has gone, and goes, into determining the optimal numbers and configuration of sample vials etc for acceptable freezing of the most vials for the least energy cost.
Much research has shown that using a controlled rate freezer prior to placing thermosensitive products in a final storage freezer is preferred because it is better for the samples. Bringing the temperature of the samples down gradually results in less shock to the specimens, thus resulting in increased cryoprotection.
However, there is much resistance in the industry to incorporate controlled rate freezing because the standard cryogenic storage containers cannot be used in the controlled rate freezing process. This is because effective controlled rate freezing requires free air flow around and between the vials, which the current cryogenic storage containers do not allow. A more open configuration is necessary for sufficient airflow during controlled rate freezing.
Several devices are typically used to secure the sample vials during controlled rate freezing. For example, a wire rack can be used, and a rounded rack consisting of a series of disks to hold samples is sometimes used. However, these and other controlled rate freezing apparatus for securing the sample vials are unsuitable for use in cryogenic freezing storage because they are not designed or configured to meet the standards required for cryogenic storage.
For example, the existing racks used in controlled rate freezers are in a non-industry standard configuration. Examples of such non-industry standard configurations include a 12×16 configuration, a 6×10 configuration, cane or circular configuration, to name a few, so that technicians, scientists, or other parties must perform a multi-step process to incorporate the advantages of controlled rate freezing.
The thermosensitive product vials typically must be taken out of a standard configuration container and placed in a non-standard configuration rack or other device, which is placed in the controlled rate freezing apparatus. After the controlled rate freezing process is concluded, the thermosensitive product vials are removed from the controlled rate freezing apparatus, such as the rack or disc. The vials are carefully placed back into a standard configuration storage container and the storage container is placed in a cryogenic freezer for storage. This multi-step process, with the typical transfers of multiple vials, results in increased labor, increased costs, and an increase in the possibility of vial misplacement and harm to the specimens.
The possibility of misplacement or mishandling of one or more of the vials during this process is of particular concern. Careful track of the vial placement must be kept so as not to misplace the thermosensitive products. Vial mix-ups could lead to disastrous consequences. For example, misplaced DNA samples could help set a guilty person free or medical sample mix-ups could lead to an incorrect diagnosis.
Accordingly, there has been a long-felt need in the industry to eliminate the extra steps involved in relocating the thermosensitive product vials between two different containers to obtain the benefit of controlled rate freezing.